The broad research objectives are concerned with investigation of genes for neoplastic transformation in strongly transforming RNA tumor viruses and tumors in animals induced by chemical carcinogens. The specific aims will be directed toward the elucidation of the origin of genes for neoplastic transformation in avian sarcoma viruses and in avian tumor cells, and comparison of the transforming gene sequences from various sources. The methods to be used include: 1) induction of tumors in chickens, ducks, quail, turkeys and pheasants with various chemical carcinogens. 2) Cultivation of tumor cells in vitro and infection of cells with non-transforming avian leukosis viruses. 3) Isolation of recombinant avian sarcoma viruses, between avian leukosis virus and the transforming genes in avian tumor cells. Cloning of recombinant viruses in appropriate cells. 4) An endogenous DNA polymerase reaction in the presence of actinomycin D and selection of transforming gene-specific DNA sequences after hybridization with vast excess of the original avian leukosis virus RNA. 5) Hybridization of the transforming gene-specific DNA probes with DNAs of normal and tumor cells of same individual bird to determine the transforming gene- specific sequences in those cells. 6) Determination of the universality of gene sequences for neoplastic transformation in avian system by using the transforming gene-specific DNA probes.